Graphene oxide based [EMIM]Cl ionanofluids in a tube and their heat transfer, and friction factor analyses under high Prandtl numbers: Experimental and ANN predictions

In this study, the stable Graphene Oxide (GO) ionanofluids were prepared and investigated the thermophysical properties, heat transfer coefficient, and friction factor experimentally. These ionanofluids were prepared by dispersing the synthesized GO into the ionic liquid of 1-ethyl-3-methylimidazolium chloride [EMIM]Cl in the weight percentages of 0.05 %, 0.1 %, 0.3 % and 0.5 %, respectively. The obtained experimental data of Reynolds number, and weight percentage was used as input parameters, and heat transfer coefficient, Nusselt number, and friction factor was used as output parameters for the Artificial Neural Network- Scaled Conjugate Gradient (ANN-SCG) analysis. The results indicated that, the thermal conductivity is enhanced by 26.39 % at a temperature of 60°C, and the viscosity enhancement of 30.44 % at a temperature of 30°C, and at 0.5 % weight percentage. The results were also indicated that, the Nusselt number, heat transfer coefficient is enhanced by 32.27 %, and 41.96 %, with a friction factor penalty of 14.04 % at 0.5 % weight percentage and at a Reynolds number of 297.4, respectively, over base fluid. The ANN-SCG results are almost predicts high accuracy when compared with the experimental data. The correlation coefficient (R 2 ) of Nusselt number, heat transfer coefficient, and friction factor are 0.9815, 0.9812, and 0.9918, respectively. Using the experimental data, a new Nusselt number and friction factor correlations were proposed.